For Ashton Carter, a perennial search for balance

“He was dazzling,” Oakes Ames, a member of the committee and the former president of Connecticut College, said of his overall performance. “I’ve heard many candidates over the years, and I don’t remember much about them. But I do remember Carter.”

For Carter, President Obama’s nominee for secretary of defense whose confirmation hearing begins Wednesday before the US Senate Committee on Armed Services, the bravura performance was standard fare. The truism about Carter is that he’s the smartest person in the room; the truth is he’s probably the smartest one in the building. This is a man who did calculus problems to relax as a youth, who snuck away from his fellow lacrosse players in high school to read medieval history, who wrote one of his two senior theses on the use of Latin by monastic writers in 12th-century Flanders. And that EKG collection? He still has it.

Carter, 60, who has served in the Pentagon under two administrations, is well known to insiders as a savvy tactician whose fierce ambition and occasionally sharp elbows have taken him to the highest ranks of the nation’s defense apparatus. But among those with whom he has worked closely both in and outside the government, he is also regarded as an independent thinker, one who is unafraid to stand up to authority. That quality, along with positions that at times appear to place him to the right of Obama, is likely to come under scrutiny by the Senate. Carter, who declined to be interviewed for this story, is not expected to encounter much opposition, though the hearing could become a vehicle for critics of Obama defense policies.

Graham Allison, director of the Belfer Center for Science and International Affairs at Harvard University where Carter worked on and off for over two decades, suggests that Carter be viewed as neither a dove nor a hawk, but as an independent-minded owl.

“Ash is basically pragmatic, not an ideologue,” said Allison. “The way reality works, owls sometimes kill hawks. But I’d say that the owl comes closer to Ash in that he does not have predictable views. He lives on facts and analysis.”

Ever since Carter’s name was first floated as a possible secretary of defense — he was passed over for the post two years ago — the highlights of his Pentagon career have been closely scrutinized. But his larger life’s story reveals as much about the man he is today and how he might handle the kind of crises he is likely to face as defense chief. Whether his love of medieval history will somehow serve him in the new post is anyone’s guess. But that he studied such a topic at all opens a window on his formative self.

Carter, the father of two adult children, is a man in perennial search of balance. Just as he juggled his diverse intellectual passions as a student, so in his adult life he has shuttled between the reserved halls of academia and the edgier corridors of government, between action and reflection.

In a paper he wrote as a postdoctoral candidate, Carter was enchanted by an equilibrium in nature that he believed could govern the universe. The subject was, “ ‘time reversal invariance,’ the proposition that the world could run backwards according to the same laws by which it runs forwards,” he later explained in a brief autobiography. “While this may seem like a bizarre question to ask, such a symmetry in nature, if it exists, is actually a very fundamental property of our universe.”

The man of balance also had a bit of a wild side.

In his junior year at Abington High School in Pennsylvania, Stephen Kahn was assigned a new lab partner in his physics class. His name was Ashton B. Carter. On the first day of class in 1970, Kahn discovered that his partner had left him a gift: a thumbtack taped to his chair, pointy side up.

“I thought, who is this guy?” recalled Kahn, who went on to become one of Carter’s close friends. “The truth was Ash was so smart that he was just bored in high school. So he pulled these kinds of pranks.’’

The offspring of three generations of physicians on his father’s side, Carter was exposed to the fundamentals of science at an early age. His father was a psychiatrist and neurologist, while his mother was an English teacher.

By the time he got to high school, Carter had the makings of a first class nerd. He wasn’t just blindingly smart, he played by the rules. And he looked the part. While most students wore bell-bottoms and sported long hair, Carter favored short hair and a collared shirt. His hobby collecting EKGs, begun while working at a local hospital, left some classmates shaking their heads.

But Carter also played sports including lacrosse, soccer, and wrestling. And he was good.

“He was a bit of a geek, but he knew his way around and people liked him,” said classmate Rick Williams, now an emergency room doctor. “He was a totally independent guy who was self motivated.”

Carter was also driven by an intellectual curiosity unrelated to grades. Classmate Jeffrey A. Sonnenfeld recalls stumbling upon his lacrosse teammate hunched over a desk in the library of a local university one weekend. Carter was poring over obscure medieval history books that he could not find on the high school shelves.

“He was totally embarrassed,” recalled Sonnenfeld, senior associate dean for leadership programs at the Yale School of Management. “I was totally shocked. I said, ‘What are you doing here?’ He said he was just curious.”

At home, he was less self-conscious about his churning brain power.

“Sometimes you’d find Ash sitting around doing calculus problems to relax in high school, you know, when the rest of us were doing our best to get out of doing calculus,” recalled Cynthia DeFelice, one of Carter’s three siblings. “I just thought, that’s Ash.”

After his 1972 high school graduation, at which he won a host of awards, Carter headed to Yale University. Torn between the dusty archives of history and the allure of the clean and logical realm of physics, Carter opted to major in both.

“I disdained the ‘preppies’ and other privileged students who seemed to regard college as an opportunity to enjoy freedom at long last,” Carter wrote in a short biography for Harvard University. “I was an intensely serious student, what would probably be called today a ‘grind.’ ”

Although he partied little and drank less due to a nagging stomach disorder, his roommates say he had a keen sense of humor. He was a familiar figure in the dormitory hallway in the green hospital scrubs he wore as pajamas and smoking a Marlboro cigarette.

Carter was particularly fascinated with the medieval era, the formative period for much of the Western world’s central institutions such as the church and nation state. And yet, the secrets of the particle world soon won him over.

Yale physics professor emeritus Robert Adair, who taught an advanced physics course, remembers Carter approaching him in his sophomore year and asking if he could take his course. Adair strongly discouraged the history major, saying the class was too hard, but Carter prevailed. By the time the final exam rolled around, over a quarter of the class had dropped out. Carter got a perfect score on the test.

Adair, then working on a research project seeking to identify sub-atomic particles known as “quarks” at the Fermi National Accelerator Laboratory outside Chicago, was so impressed by the young scholar that he invited Carter to join him on the project in the summers. Carter volunteered to accompany Adair on the night shift keeping watch over the lab’s massive accelerators.

“He asked questions about physics and elementary particles all through the night until he saw me turn green with exhaustion, and then he would read books in Latin,” recalled Adair, 90. “I thought he was especially unusual.”

Meanwhile, outside the laboratory, American society roiled with political unrest as the scandal engulfing Richard Nixon’s presidency unfolded and the war in Vietnam tore at the heart of the nation. Carter leapt in.

In June of 1973, Carter typed a passionate letter to the president urging him to resign. History, he wrote, “will not be kind to you, Mr. President. You have committed outrages against the freedom of individuals, the United States of America, and the humanity of the people of Southeast Asia.”

A year and a half later, Carter wrote a two-part series in the Yale Daily News calling for reform of the nation’s intelligence operation. He urged the public to pay closer attention to how government should operate. Failing to do so, he added, “is why the Government is often able to get away with saying it is doing the public’s will while acting quite differently.”

Having graduated with highest honors, Carter headed hopefully into his interview for the Rhodes Scholarship. Although a couple of committee members, now quite senior, do not recall the EKG incident, Carter told one of his closest friends and a Yale professor about it in detail at the time. And in the fall of 1976, he walked eagerly on to the St. John’s College campus in Oxford, England. For Carter, the next three years would be an intellectual flowering during which he began to think about the questions of weapons and arms control that would define much of his career.

He also had fun. In a letter to his old lab partner Stephen Kahn, Carter described a desk littered with engraved invitations. There was a visit to the home of the US ambassador in London, dinner with the president of the Royal Historical Society, and sherry at the British Council.

“What an ego trip!” Carter wrote. “It’s a feeling of destiny — that the whole world is there to be had, and I want it.”

While most Rhodes scholars pursue a master’s or second undergraduate degree while in Oxford, Carter decided to pursue a doctorate in theoretical physics. At Oxford, he encountered Sidney D. Drell, an American physicist involved in arms control then a visiting fellow, and now a senior fellow at Stanford University.

“Ash got to talking to Sid over coffee about arms control so I think mentally he was starting to move in that direction,” said professor Sir Chris Llewellyn Smith, Carter’s adviser and now director of energy research at Oxford University. “Ash was thinking ahead.”

Five years after he left Oxford, Carter was at the heart of a raging controversy that engulfed the US defense and scientific communities. At issue was President Reagan’s 1983 proposal to construct a space-based missile defense program, commonly called the “Star Wars” program. Carter wrote a 1984 government paper for the US Office of Technology Assessment that essentially said the plan was unworkable.

In his Harvard autobiography, Carter claims his “was the first authoritative report to say that the emperor had no clothes.” In fact, many in the scientific community had already expressed serious doubt about the proposal, although they did not have access to classified information as Carter did. His report nonetheless put him on the fast track.

Within months he was hired by Harvard’s Kennedy School of Government. There, Carter became known for an assertiveness tinged with impatience — at times answering questions asked of others — as well as for his support of younger colleagues.

One of Carter’s prime areas of interest was the impending collapse of the Soviet Union and the question of what would happen to its nuclear weapons arsenal, known as the “loose nukes” problem. The subject, which called upon his skills both as a scientist and an emerging policy maker, would color his career both in and out of government.

“One of the great values of Ash at Harvard was that people did not see him as having a political answer [but] as trying to get to the right answers,” said Joseph S. Nye Jr., former dean of the Kennedy School of Government who served in government as assistant secretary of defense during the Clinton administration as did Carter.

Not that he has endeared himself to all with whom he worked. As Carter rose in the ranks and was named director of Harvard’s Center for Science and International Affairs in 1990, some felt his mounting ambitions undercut his work in Cambridge.

Ted Postol, professor emeritus of science and technology at the Massachusetts Institute of Technology, who worked with Carter in both government and academia, remembers cohosting a seminar on international security with Carter in 1989. Postol says that Carter was often late to class and sometimes failed to show up when guest speakers were visiting the class.

“One time he did not show up and I walked into his office and he was on the phone with one of his buddies in DC,” said Postol. “He was very disrespectful of others and very self-involved. He has a very limited ability to empathize with others.”

Another colleague, who declined to be identified, described a similar incident. But Carter’s star continued to rise, and in 1993 he was named assistant secretary of defense for international security policy. In 1994 he played an instrumental role in the standoff with North Korea over nuclear weapons under Defense Secretary William J. Perry. He went back to Harvard in 1996 only to return to government a couple of years later.

Carter and Perry, director of the Preventive Defense Project at the Center for International Security and Cooperation at Stanford University and one of Carter’s mentors, have long taken a hard line in dealing with North Korea; in 2006 they lobbied for a possible preemptive strike against the country. But Perry cautions that “hawk” may be too strong a word to use in describing Carter.

“If he was, then I was too,” said Perry, who formerly codirected the Defense Project with Carter. “He is a strong believer, as I am, that in order for diplomacy to be successful we need a strong military capability. “

Over the past three decades, Carter has moved fluidly between the halls of the university and the Pentagon corridors, where he was nicknamed “The Deliverer” for his ability to get the job done. Every few years or so, it seems, he grows impatient with the more languid pace of the academy and hungers for the arena.

Which is not to say that he does not have decidedly mixed feelings about public service. In his autobiography, Carter wrote that working in Washington, D.C., “is a little bit like being a Christian in the Colosseum. You never know when they are going to release the lions and have you torn apart for the amusement of onlookers.”

On Wednesday, Carter heads back into the government maw, this time aiming for the Colosseum’s highest perch.

Sally Jacobs can be reached at sally.jacobs@globe.com.